This invention is an improved input keyboard ergonomically designed to equalize the effort and time required of each finger in relation to that finger's shape, dexterity, and strength; with all the fingers resting on or reaching all the keys naturally, with the least amount of effort possible, and in the fastest time possible. An unlimited number of symbols and operating bits grouped into modes can be entered into any device controlled by a keyboard. The assignment of the bits in any mode among the keys permits the fastest possible entry. 2. Description of the Prior Art
The standard, so-called QWERTY, keyboard for transmitting of information is very inefficient. It typically has 44 keys in two shift modes for the transmission of 88 characters and 15 to 20 other keys and levers for such funtions as spacing, mode shifting, and paper adjusting. With minor modifications this keyboard is used around the world and normally has four parallel rows of keys in a rectangular pattern.
With more sophisticated typewriters and computers the keyboard must perform more functions and transmit more types of information. To do this more keys, levers, and other control devices have been added; so that there now are keyboards with more than 125 keys in addition to the other devices. In addition, each key often has to perform more tasks. With the use of shift, control, alternate, and other mode changing keys; it is now common to have each key perform four or more tasks.
Very few typists ever learn to operate the standard four row keyboard efficiently, but the so-called improvements make it almost impossible to enter information automatically by what it commonly called touch typing. This has slowed down the transmitting of information and increased the number of errors produced. Other devices, such as the mouse and joysticks, have not helped to solve the problem.
Many have tried to invent the optimum keyboard by changing its shape, the relative position of the keys, and the assignment of the characters to the keys. However, they have all failed. The optimum keyboard must be capable of transmitting in excess of 3000 bits of information in more than 100 groups; ranging from alphabets and graphic symbols to programing and mathematical operators. The optimum keyboard should also be capable of having information entered quickly and correctly, it should be suitable for use with all types of equipment requiring information transfer, and it should be easy to learn and operate. The present invention is capable of doing all of this.
All of the existing and proposed keyboards fail being optimum because the distribution of the symbols and functions among the various keys is incorrect for the optimum entering of information. They fail because they do not separate the control and operating functions. They fail because they are designed with geometric elements such as straight lines and circles, and the fingers and hands are shaped irregularly. Consequently, the fingers do not touch and reach the keys naturally, and they must stray from the home keys and thus are unable to locate the correct keys consistently. They fail because the keys are placed equidistant from each other, and the normal and natural finger travel varies with the direction traveled and among the fingers. They fail because there are too many keys, and the operator becomes confused as to which key to use and where to located that key. They fail because the finger and hand loads are unbalanced; causing the weaker fingers and hand to become more tired than the stronger ones. They fail because they are only able to transmit a limited number of information bits equal to the number of keys times the number of mode changing keys and their combinations; with the mode changing keys limited to the shift, control, alternate, and similar keys. The present invention overcomes all of these failures.
The arrangement of the characters is on a board is a main determinant of how fast information can be transmitted, how easy a board can be learned and memorized, how error prone the board is, and how fatiguing it is to operate. The most used group of information if the Latin alphabets, but the conclusions about the Latin alphabets applies to all the other groups of information.
Before discussing the arrangement of the characters it is necessary to look at the dexterity and strength of the hands and fingers. Experience tells us that the strongest and most dexterous hand and fingers can enter information the fastest, with the least errors and fatigue, and they can learn and memorize tasks faster than the weaker and clumsier hand and fingers. That means that the most frequently used characters should be located under the fastest and strongest fingers.
About 85% of the population is right-handed, about 10% is left-handed, and about 5% is ambidextrous. Although it is just as easy to design a keyboard favoring a minority of the population, for now, we are limiting our discussion to the optimum keyboard for the majority. There are no absolute values of the difference in strength and dexterity of an average person's fingers and hands because of the many factors involved, but tests indicate that the average of the entire population is in the order of six to five in favor of the right hand. That means that the right hand can do six things in the same time as the left hand does five things with the same effort. Or put another way, in the same period of time, the right hand should do about 55% of the keyboard strokes, and the left hand should be about 45%. However, it is doubtful if there would be any measurable difference if those figures varied 2 or 3%; so we can assume the optimum percentage for the right hand to be between 52 and 58.
To simplify our discussion of the fingers we will code them with the letter L for the left ones and the letter R for the right ones. We will further code them with the numerals 1 to 5 starting with the thumb.
Finger R1 on a right-handed person is the fastest, and an average person can easily learn to tap six strokes a second in a relatively short period with this finger. Six strokes a second correspond to 72 five letter words a minute, and it is the maximum an average person will ever do. That same person can tap R2 at the same speed, R3 one or two percent slower, R4 about three percent slower, and R5 about seven percent slower. In relation to R1, L1 is about fifteen percent slower, L2 and L3 about eighteen percent slower, L4 about twenty-five percent slower, and L5 about forty percent slower.
The above information is important in determining the time required to stroke the home keys one at a time and to some extent determine how many strokes it takes for a finger or hand to reach a certain level of fatigue; but most entering of information requires the pressing of two keys, digraphs, in rapid succession. A much smaller amount of information requires the pressing of three or more keys in succession, but because of the very small percentages involved, because very few typists ever do these sequences, and because the overall combinations do not change if we include them in our calculations, we will ignore these sequences.
Even though an operator may be able to stroke two particular keys faster than two other particular keys, it does not necessarily follow that it will happen, and studies of what happens in practice indicates that it is desirable to have the letters of a digraph entered by alternate hands, and failing that to have them entered by alternate fingers.
The Gentner et al study of 11 experienced typists with speeds between 60 and 110 words per minute and averaging 90 words per minute typed digraph interstrokes at the following times. Two hand mean time of 114 milliseconds (msec.) with a range of 90-157 msec. Two finger mean time of 131 msec. with a range of 99-215 msec. One finger double character mean time of 157 msec. with a range of 148-160 msec. One finger home key and adjacent key characters mean time of 185 msec. with a range of 179-222 msec. One finger adjacent and adjacent key characters mean time of 192 msec. with a range of 179-251 msec.
The digraph frequency in different languages vary greatly but is always related to the frequencies of the individual letters. English is the most used Latin-alphabet language, its digraphs are representative, and it is selected for this discussion.
The average word consists of about 4.35 letters, 0.13 punctuation marks, and 1.05 spaces. That means that about 21% of all digraphs involve non-letters, and on the present invention they are executed on the optimum combination of keys. These digraphs act as natural stops for the average typist, and as such they are not stroked in a rhythmic sequence. For an average typist the same natural stops, or breaks in the rhythmic sequence, occurs when shifting for an uppercase letter, entering a return, or entering another symbol such as a numeral. The percentage of these stops for most text is in the order of 35 to 40%. The number of digraphs from one study to another varies, but the relative frequencies are fairly constant, and when are able to gauge the numbers within a percent or two.
Because of the character assignment to the keys of the present invention the entering of information by the non-thumb fingers is done the most efficient. The thumbs function essentially as independent units and also function at their optimum speeds on the keyboard of the present invention.
The average frequencies determined from the 18 major Latin alphabets are as follows, in percent: space 18; E 11; A and O each 7; I,N,R, and S 5 each; T 4; D and L 3 each ; C,F,G,H,M,P,U,W, and return, 2 each; B,K,V,Z, comma, period, and shift, 1 each ; and all the others account for 4. The 2% for the return is based on information entered on a typewriter keyboard. It is much less than 1% for information entered on a device capable of wraparound entry. With this information it is possible to have the ten home keys be responsible for anywhere from two thirds to three quarters of all keystrokes, depending on the language and type of text, and it is possible to arrange the characters in such a manner that the maximum number of digraphs are sequenced on alternate hands.
TABLE 1 ______________________________________ LEADING KEYBOARD CHARACTER ARRANGEMENTS In % Finger Total Keyboard L5 L4 L3 L2 L1 R1 R2 R3 R4 R5 L R ______________________________________ QWERTY 8 7 15 19 9 9 13 5 11 4 58 42 Von 6 1 4 17 11 22 18 4 5 9 39 61 Kunowski Muther 2 5 8 20 9 9 24 13 5 5 44 56 Dvorak & 8 8 12 11 9 9 11 8 11 11 49 51 Dealy Dodds 9 9 12 11 2 19 11 8 11 7 43 57 Einbinder 7 8 12 10 23 10 9 6 7 9 59 41 No. 1 Einbinder 9 6 13 9 23 9 8 8 8 7 60 40 No. 2 Malt 9 6 6 11 12 21 12 5 7 9 45 55 Bruckschen* 7 2 2 6 14 18 6 2 2 7 31 35 Casey 0 0 6 23 12 10 27 15 5 0 42 58 Marsan* 9 11 7 9 ? ? 11 3 6 19 36 39 Diernisse 6 9 9 16 3 19 15 9 7 6 43 57 ______________________________________ *Do not show return, space and other essential elements, so the loads for the thumbs and total hand loads are understated. The percent distribution of characters on the keys of the various keyboards include the present invention. The figures do not always add up to 100% because of rounding.
Besides the present invention there are only four of the keyboards which have distributed the characters between the hands within the 51 / 48 to 58 / 42 range previously determined to be the optimum. Of these, Muther have five rows of keys in a near rectangular arrangement, which is very inefficient. Dodds have almost the same shape keyboard with one less row, but that is still very inefficient. All, except the present invention, suffers from a poor distribution of the finger load.
If we take all the keyboards of the prior art and calculate the time for the interstrokes of digraphs from standard English test, using the mean times from the Gentner et al study, we find that only the Dvorak board is faster, and it by only 3%.
There are roughly 160 characters in the Latin alphabets, and generally speaking half of them are uppercase letters and the rest are lowercase letter. All of the alphabets have 44 of the characters. The Q, W, X, and Y with their corresponding lowercase letters are absent from some of the less used alphabets, but not all of them from the same alphabets. Some characters are characteristic to only one or a few alphabets. A typical example is the Danish and Norwegian O with a slash diagonal through it. The largest portion of the characters found only on a limited number of alphabets are standard characters with an accent mark such as the cedilla or umlaut. There are ten such accent marks.